毒性是物质对组织造成伤害的程度。经过词义延伸，这个词还可以用来比喻形容较大组织的负面作用，比如家庭和社会。有时毒性这个词与人们日常生活所用的毒害一词同义。

Toxicity is the degree to which a substance can damage an organism. By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or society at large. Sometimes the word can be synonymous with poisoning in everyday usage